DAX code
Discount % =
DIVIDE(SUM('Sales'[DiscountAmount]), SUM('Sales'[GrossAmount]))
Expresses total discount given as a percentage of gross sales before the discount.
Type your table and column names once. Every measure below updates.
Discount % =
DIVIDE(SUM('Sales'[DiscountAmount]), SUM('Sales'[GrossAmount]))
Replace the column names with your own gross amount and discount amount columns.
Browse all 175 measures in the Power BI DAX Measures Library, or search the library for something similar to Discount %.